检索结果-内蒙古大学图书馆

Three-Dimensional Modeling of Geogrid Pullout Test Using finite-element method

INTERNATIONAL JOURNAL OF GEOMECHANICS 2022年第3期22卷

作者： Amirhosseini, Iman Toufigh, Vahid Toufigh, Mohammad Mohsen Ghazavi-Baghini, Emad Grad Univ Adv Technol Fac Civil & Surveying Engn Kerman *** Iran Shahid Bahonar Univ Kerman Dept Civil Engn Kerman *** Iran Ports & Maritime Org Shahid Rajaee Port Bandar Abbas *** Iran

Three-dimensional (3D) modeling of soil-geogrid interaction is a numerical challenge when simulating reinforced soil systems. Modeling the soil-geogrid interaction requires an appropriate consideration of the geogrid geometry, the materials' model, and the interface properties. In this study, a series of 3D models were developed using the finite-element method (FEM) to investigate the response of geogrid under confined and unconfined conditions focusing on geogrid tensile stiffness effects. In this regard, a modeling approach for the geogrids whose configuration is complex was proposed. The validity of the models was also justified by the good agreement between calculated numerical results and measured experimental data. Moreover, particular emphasis was placed on visualizing the soil-geogrid interaction and load transfer mechanisms. The load transfer mechanisms were embodied not only through the distributions of displacement, strain, and tensile force along the geogrid but also through the displacement fields inside the soil domain. The results from two series of tests showed that the proposed approach was capable of reasonably capturing the geogrid response, whether under unconfined or soil-confined conditions.

关键词： Geogrid modeling Tensile response Soil-geogrid interaction Geogrid stiffness Pullout response finite-element method

来源：评论

学校读者我要写书评

暂无评论

Digital image processing for physical basis analysis of electrical failure forecasting in XLPE power cables based on field simulation using finite-element method

引用

IET GENERATION TRANSMISSION & DISTRIBUTION 2020年第26期14卷 6703-6714页

作者： Talaat, M. Tayseer, M. El-Zein, A. Zagazig Univ Fac Engn Elect Power & Machines Dept Zagazig Egypt Shaqra Univ Coll Engn Elect Dept Dawadmi Ar Riyadh Saudi Arabia

In this research, digital image processing method (DIPM) is used as an innovative approach to predict precisely the shape of electrical tree (ET) in cross-linked polyethylene (XLPE) power cables in the presence of air voids based on the field calculation using finite-element method (FEM). With the help of DIPM, two case studies are held to detect the accurate parameters of either the first initiated major branch or the tips of the major branches of ET. A hyperbolic needle-to-plane simulation model is proposed to illustrate the ET inception and propagation stages. The non-uniform electric fields thatare accompanied with the electrical treeing phenomenon are calculated using FEM as one of the most effective numerical methods to deal with non-uniform shapes. The predicted shapes of ET initiation and growth are provided in an innovative manner with the implemented hybrid connection between FEM and DIPM for the two proposed case studies. Direction branching approach and deviation angle branching approach are provided in this work to predict the shape and the direction of ET branched voids. The validity of the proposed model is assessed with the help of available previous experimental and simulation data.

关键词： power cables power cable insulation XLPE insulation trees (electrical) finite element analysis voids (solid) finite-element method digital image processing method DIPM electrical tree cross-linked polyethylene power cables air voids field calculation FEM accurate parameters initiated major branch hyperbolic needle-to-plane simulation model propagation stages nonuniform electric fields electrical treeing phenomenon effective numerical methods nonuniform shapes innovative manner deviation angle branching approach available previous experimental simulation data physical basis analysis electrical failure forecasting XLPE power cables field simulation

来源：评论

学校读者我要写书评

暂无评论

Combined Model Based on the finite element method and Artificial Neural Networks for Modeling Laser Shock Peening of Titanium-Niobium Implants

引用

JOURNAL OF MACHINERY MANUFACTURE AND RELIABILITY 2023年第7期52卷 741-748页

作者： Sakhvadze, G. Zh. Sakhvadze, G. G. Russian Acad Sci Mech Engn Res Inst Moscow Russia

The medical titanium-niobium alloy Ti-6Al-7Nb is investigated. The application of laser shock peening technology to these alloys leads to an increase in the service life of prostheses and implants due to the creation of near-surface compressive residual stresses, which slow down or completely stop the formation and development of fatigue cracks. Residual stress fields generated by laser shock peening are first modeled using the finite element method, then they are used as a training dataset for an artificial neural network. Therefore, a combined model for the study of compressive residual stresses is developed. Microhardness, laser energy, overlap, and depth are used as input parameters for the artificial neural network, and residual stresses are used as output parameters. The obtained results show that, after laser shock peening, compressive residual stresses with values from -42 to -516 MPa are formed in the near-surface region depending on the parameters of the laser exposure.

关键词： residual stresses laser shock peening implant titanium-niobium alloy artificial neural network finite-element method

来源：评论

学校读者我要写书评

暂无评论

Application of the finite-element method to the solution of nonsimilar boundary layer-derived infinite series equations

引用

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2020年 161卷 120244-120244页

作者： Amoo, O. M. Oyewola, M. O. Fagbenle, R. O. Univ Ibadan Dept Mech Engn Ibadan Oyo State Nigeria Fiji Natl Univ Sch Mech Engn Suva Fiji

One of the most prolific areas of fluid mechanics applications in general and nanofluid applications in particular, is boundary layer flows. In the recent past, a great many of these applications, have been limited to one-term similarity approximations. This work however, was concerned with numerically approximating nonsimilar fluid boundary layer transfer. Nonsimilar fluid boundary layer problems are more generally valid and are more prevalent industrially. In this research, the objective was to establish and advance numerically the first application of the finite-element method (FEM) to the solution of a set of nonsimilar boundary layer-derived infinite series ordinary differential equations (ODEs). Thus, this work emphasizes an FEM technique devised and used for a class of nonsimilar boundary layer-derived ODEs. The motivation is to improve and complement the numerical heat transfer literature regarding an FEM technique that may be applied to solve a coupled system of nonsimilar boundary layer-derived infinite series ODEs. The analysis obtained results that correlate very well with highly accurate benchmarked results for heat transfer and universal velocity functions. An examination of the convergence of the FEM is also shown and discussed. The results indicate that the FEM is a very robust technique for nonsimilar boundary layer infinite series differential equations. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Boundary layer infinite series ODEs finite-element method Perturbation series Merk-Chao-Fagbenle method

来源：评论

学校读者我要写书评

暂无评论

New Algorithm for Three-Dimensional Borehole-to-Surface Apparent Resistivity Imaging Based on Unstructured Mesh finite-element method

引用

IEEE ACCESS 2020年 8卷 184-194页

作者： Xiong, Zhitao Tang, Xingong Qiu, Weizhong Zhao, Chunyan Zhang, Lianqun Yangtze Univ Key Lab Explorat Technol Oil & Gas Resources MOE Wuhan 430100 Peoples R China Hubei Cooperat Innovat Ctr Unconvent Oil & Gas Wuhan 430100 Hubei Peoples R China Shanxi Coal Geol Explorat Inst Datong 037039 Peoples R China Shanxi 131 Coal Field Geol Ltd Co Hancheng 715400 Peoples R China PetroChina Res Inst Petr Explorat & Dev Beijing 100083 Peoples R China

In this paper, a finite-element method with unstructured mesh is used to numerically simulate the line source model of three-dimensional borehole-to-surface electrical potential method. A new total field potential is synthesized using the calculated anomalous field potential and the analytic solution of the background field. In solving for the original total field potential and background potential, this method can guarantee a small near-field error in the new total field potential without the need to densely mesh the region with the source. By comparing the synthesized total field and analytic solution, the high accuracy of the numerical solution is verified. The results of model calculation show that the detection effectiveness of the borehole-to-surface electrical method depends on the length of the line source. The detection effectiveness increases substantially with increasing length of the line source within a certain range. However, when the line source is excessively long, the increase in detection effectiveness for anomalies is insignificant. For a low-resistance anomaly of a given volume, the borehole-to-surface electrical method is more sensitive to changes in the lateral area than to changes in the thickness. When the gob contains only a small amount of water (e.g., Model IV containing 50025;of water by volume), it will appear as a low-resistance anomaly. In addition, the detection of a water-logged gob by the borehole-to-surface electrical method depends on the depth and size of the gob. The borehole-to-surface method can accurately delineate the profile boundary of an anomaly, even though the side closer to the source is susceptible to the effect of source current. These results are significant for guiding the field exploration of the borehole-to-surface electrical method, improving result interpretation, and assisting the application.

关键词： Borehole-to-surface electrical potential method finite-element method vertical line source unstructured mesh

来源：评论

学校读者我要写书评

暂无评论

Agent-based modelling and parameter sensitivity analysis with a finite-element method for skin contraction

引用

BIOMECHANICS AND MODELING IN MECHANOBIOLOGY 2020年第6期19卷 2525-2551页

作者： Peng, Qiyao Vermolen, Fred Delft Univ Technol Delft Inst Appl Math Van Mourik Broekmanweg 6 NL-2628 XE Delft Netherlands Univ Hasselt Fac Sci Div Math & Stat Computat Math Grp CMAT Agoralaan Bldg D B-3590 Diepenbeek Belgium

In this paper, we extend the model of wound healing by Boon et al. (J Biomech 49(8):1388-1401, 2016). In addition to explaining the model explicitly regarding every component, namely cells, signalling molecules and tissue bundles, we categorized fibroblasts as regular fibroblasts and myofibroblasts. We do so since it is widely documented that myofibroblasts play a significant role during wound healing and skin contraction and that they are the main phenotype of cells that is responsible for the permanent deformations. Furthermore, we carried out some sensitivity tests of the model by modifying certain parameter values, and we observe that the model shows some consistency with several biological phenomena. Using Monte Carlo simulations, we found that there is a significant strong positive correlation between the final wound area and the minimal wound area. The high correlation between the wound area after 4 days and the final/minimal wound area makes it possible for physicians to predict the most probable time evolution of the wound of the patient. However, the collagen density ratio at the time when the wound area reaches its equilibrium and minimum, cannot indicate the degree of wound contractions, whereas at the 4th day post-wounding, when the collagen is accumulating from null, there is a strong negative correlation between the area and the collagen density ratio. Further, under the circumstances that we modelled, the probability that patients will end up with 5% contraction is about 0.627.

关键词： Wound healing Wound contractions Monte Carlo simulations finite-element method Agent-based modelling

来源：评论

学校读者我要写书评

暂无评论

A split-step finite-element method for incompressible Navier-Stokes equations with high-order accuracy up-to the boundary

引用

JOURNAL OF COMPUTATIONAL PHYSICS 2020年第0期408卷 109274-000页

作者： Li, Longfei Univ Louisiana Lafayette Dept Math Lafayette LA 70504 USA

An efficient and accurate finite-element algorithm is described for the numerical solution of the incompressible Navier-Stokes (INS) equations. The new algorithm that solves the INS equations in a velocity-pressure reformulation is based on a split-step scheme in conjunction with the standard finite-element method. The split-step scheme employed for the temporal discretization of our algorithm completely separates the pressure updates from the solution of velocity variables. When the pressure equation is formed explicitly, the algorithm avoids solving a saddle-point problem;therefore, our algorithm has more flexibility in choosing finite-element spaces. In contrast, popular mixed finite-element methods that solve the INS equations in the primitive variables (or velocity-divergence formulation) lead to discrete saddle-point problems whose solution depends on the choice of finite-element spaces for velocity and pressure that is subject to the well-known Ladyzenskaja-BabuSla-Brezzi (LBB) (or inf-sup) condition. For efficiency and robustness, Lagrange (piecewise-polynomial) finite elements of equal order for both velocity and pressure are used. Accurate numerical boundary condition for the pressure equation is also investigated. Motivated by a post-processing technique that calculates derivatives of a finite element solution with super-convergent error estimates, an alternative numerical boundary condition is proposed for the pressure equation at the discrete level. The new numerical pressure boundary condition that can be regarded as a better implementation of the compatibility boundary condition improves the boundary-layer errors of the pressure solution. A normal-mode analysis is performed using a simplified model problem on a uniform mesh to demonstrate the numerical properties of our methods. Convergence studies using P-1 elements support the analytical results and demonstrates that our algorithm with the new numerical boundary condition achieves the optimal second

关键词： Navier-Stokes equations Pressure-Poisson reformulation Split-step method finite-element method Normal-mode analysis

来源：评论

学校读者我要写书评

暂无评论

Superconvergence analysis of a two-grid finite element method for nonlinear time-fractional diffusion equations

引用

COMPUTATIONAL & APPLIED MATHEMATICS 2022年第8期41卷 1-20页

作者： Gu, Qiling Chen, Yanping Huang, Yunqing South China Normal Univ Sch Math Sci Guangzhou 510631 Peoples R China Xiangtan Univ Sch Math & Computat Sci Hunan Key Lab Computat & Simulat Sci & Engn Xiangtan 411105 Peoples R China

Based on spatial finite-element methods combined with classical L1 time stepping method, the superconvergence analysis of the two-grid approximate scheme for the two-dimensional nonlinear time-fractional diffusion equations is considered. First, we use the rectangular Lagrange type finite element of order p to get a two-grid fully discrete scheme of the equation and discuss the superclose error estimate with the order O (h(p+1) + H2p+2 + tau(2-alpha)) in the H-1 norm, here tau, H and h denote time step, coarse and fine grid sizes, respectively. Second, through the interpolated postprocessing approach, the global superconvergence of order O (h(2) + H-4 + tau(2-alpha)) in the H-1 norm is obtained. Finally, two numerical experiments are provided to confirm our theoretical results and effectiveness of the proposed algorithm.

关键词： Two-grid method finite-element method Nonlinear time-fractional sub-diffusion L1 scheme Superclose and superconvergence

来源：评论

学校读者我要写书评

暂无评论

Coupled Moving Particle Simulation-finite-element method Analysis of Fluid-Structure Interaction in Geodisasters

引用

INTERNATIONAL JOURNAL OF GEOMECHANICS 2021年第6期21卷

作者： Zhu, Chongqiang Chen, Zhiyi Huang, Yu Tongji Univ Coll Civil Engn Dept Geotech Engn Shanghai 200092 Peoples R China

Geodisasters associated with fluidized geomaterials, such as flow-like landslides, flow slides, and debris flows, pose a tremendous threat to communities and the environment. Protective structural measures are therefore important for disaster prevention and mitigation. However, the development of a numerical method to study fluid-structure interaction (FSI) remains a challenge. A coupled method is proposed using moving particle simulation (MPS) to simulate the large deformation of fluidized geomaterials and a finite-element method (FEM) to model the dynamic behavior of structures. A new boundary condition based on the Shepard filter method is developed for MPS to improve its efficiency. An interaction model with weak coupling schemes is used to effectively communicate information and coordinate the different time steps between the MPS and FEM approaches. The effectiveness and accuracy of the hybrid numerical method for FSI are verified and validated using a series of benchmark problems.

关键词： Geodisasters Interaction Hybrid method Moving particle simulation finite-element method

来源：评论

学校读者我要写书评

暂无评论

A 1D Model for Predicting Heat and Moisture Transfer through a Hemp-Concrete Wall Using the finite-element method

引用

MATERIALS 2021年第22期14卷 6903-6903页

作者： Benkhaled, Maroua Ouldboukhitine, Salah-Eddine Bakkour, Amer Amziane, Sofiane Univ Clermont Auvergne Inst Pascal SIGMA Clermont CNRS F-63000 Clermont Ferrand France Lebanese Univ Fac Sci Dept Phys Beirut Lebanon

Plant-based concrete is a construction material which, in addition to having a very low environmental impact, exhibits excellent hygrothermal comfort properties. It is a material which is, as yet, relatively unknown to engineers in the field. Therefore, an important step is to implement reliable mass-transfer simulation methods. This will make the material easy to model, and facilitate project design to deliver suitable climatic conditions. In recent decades, numerous studies have been carried out to develop models of the coupled transfers of heat, air and moisture in porous building envelopes. Most previous models are based on Luikov's theory, considering mass accumulation, air and total pressure gradient. This theory considers the porous medium to be homogeneous, and therefore allows for hygrothermal transfer equations on the basis of the fundamental principles of thermodynamics. This study presents a methodology for solving the classical 1D (one-dimensional) HAM (heat, air, and moisture) hygrothermal transfer model with an implementation in MATLAB. The resolution uses a discretization of the problem according to the finite-element method. The detailed solution has been tested on a plant-based concrete. The energy and mass balances are expressed using measurable transfer quantities (temperature, water content, vapor pressure, etc.) and coefficients expressly related to the macroscopic properties of the plant-based concrete (thermal conductivity, specific heat, water vapor permeability, etc.), determined experimentally. To ensure this approach is effective, the methodology is validated on a test case. The results show that the methodology is robust in handling a rationalization of the model whose parameters are not ranked and not studied by their degree of importance.

关键词： hemp concrete heat air and mass transfer numerical implementation finite-element method

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：